Reproduction of printed matter using thermal neutrons



Nov. 19, 1963 R. F. LUMB 3,111,583

REPRODUCTION OF PRINTED MATTER USING THERMAL NEUTRONS Filed Feb. 9, 1960United States Patent 3,111,583 REPRODUiIITISN 0F PRENTED MATTER USENGTHERMAL NEUTRGNS Ralph F. Lumb, Wallingford, Conn, assignor, by mesneassignments, to Moore Business Forms, Inc, Niagara Falls, N.Y., acorporation of Delaware Filed Feb. 9, 1%0, Ser. No. 7,625 14 Claims.(Cl. 250-65) This invention relates to a method of and mechanism for thereproduction of printed, written, typed or like material andparticularly to reproduction of such material in sheet form such, forexample, as is commonly done by photographic or similar methods. Theinvention also relates to a mechanism which may be conveniently employedto carry out this method.

The method is based upon the reaction of thermal neutrons with somesubstance such as boron or lithium to produce high-energy alpha or betaparticles which in turn act upon a sensitized sheet or a sheet of paperor the like hearing a photographic layer of material to produce theimage of the copy of printed or written matter upon a master sheet.

In the process a master is first made by written, typing, printing orsketching the material upon a master sheet with inks into which havebeen incorporated some element such as boron or lithium, for example,with which neutrons from a suitable source will react to producehigh-energy alpha or beta particles. In turn these particles will affectthe sensitized sheet and produce thereon the necessary sharp image. Themechanism is so constructed as to prevent the generation of harmfulradiation so that no special precautions need be taken by the operatorin its use. In the preferred form of mechanism herein disclosed a pairof cooperating rolls are employed between which the master sheet andsensitized sheet are fed. One of the rolls is provided at its axis witha source of slow moving neutrons, and this roll is so shielded as toprevent exposure of the operator to harmful radiation. The master sheetis placed in contact with this roll and between it and the other orpresser roll is introduced the sensitized sheet to be acted upon by thehigh-energy alpha or beta particles produced by the boron or othermaterial in the ink on the master sheet to produce the image on thesensitized sheet.

One object of the invention is to provide a new and improved method ofreproducing written, typed, printed or sketched materials.

A further object of the invention is to reproduce such materials by amethod which includes the production of the material to be duplicated bythe use of ink containing a substance which, upon reaction with thermalneutrons, will produce high-energy alpha or beta particles which in turnwill efiect the production of an image upon a sensitized sheetmaintained in close contact with the master sheet.

Still another object of the invention is to provide an improvedmechanism for carrying out the described process.

To these and other ends the invention consists in the novel features andcombinations of parts to be hereinafter described and claimed.

In the accompanying drawings:

FIG. 1 is a front elevational view, partly in section, of mechanism forreproducing or duplicating printed, typed, written or sketched material,some parts being broken away and shown in section; and

FIG. 2 is a sectional view on line 22 of FIG. 1.

To illustrate a preferred embodiment of a mechanism for carrying out myimproved process, I have shown in the drawings a casing it within whichare rotatably mounted a pair of cooperating rolls 11 and 12. These rollsmay be provided with suitable pintles 13 and 14 to which are securedrespectively the gears 15 and 16, these gears meshing with each otherand preferably being so proportioned with respect to the diameter of therolls to rotate the latter at the same peripheral speeds. The gear 16may be driven from any suitable source indicated conventionally at 17.

The body 18 of the roll 11, as illustrated, may be conveniently formedof some plastic substance such as polyethylene and provided about itsperiphery with a cover of some hard material such as Lucite. At the axisof this roll is located a source of neutrons 20 which may be of anymetal suitable for this purpose and which is in rod-like form and issubstantially coextensive in length with the roll itself. For example, amixture of plutonium and beryllium may be placed in a tubular capsuleand the capsule sealed to provide this element. The roll 12 may be ofany suitable material such as hard or at least firm rubber, for example.

An entrance chute 21 is provided for entrance of a master sheet 22 uponwhich the material to be copied has been placed and a superposedsensitized sheet 23, which sheets are directed into the bite between therolls. Similarly a discharge chute 24 is provided to receive the mastersheet and sensitized sheet from the rolls and dis charge them from themachine at the opening 25. The lower wall 26 of the entrance chute aswell as the inner wall 27 of the discharge chute and the front portion28 of the casing between the entrance and discharge chutes are steelclad to afford a boral neutron shield so that the neutron will onlystrike the sensitized sheet at the time of transfer of the materialthereto. The inner ends of the members 26 and 27 approach the rollsclosely, but between them there is a minimum gap, through which therolls engage, to permit the impinging of the neutrons on the mastersheet. The member 27 may wipe against the lower roll as shown at 29 toguide the two sheets into the discharge chute. The outer wall of thedischarge chute 24 may be continued beyond the casing, as shown at 30,to form a shelf for the discharged copy.

In carrying out the process the copy or material which is to beduplicated will be written, typed, printed or sketched upon a mastersheet by the use of an ink into which has been incorporated some elementsuch as boron or lithium, for example, with which the neutrons willinteract to produce the high-energy alpha or beta particles. Forexample, boric acid might be dissolved in standard fountain pen ink, andthis ink utilized to make the master sheet which is to be copied.

The photosensitive sheet or sensitized paper is then placed in closecontact with the master sheet and the two fed in between the rolls 1].and 12 so as to be exposed to the source of neutrons 20. The high-energyalpha or beta particles generated by the neutrons within those portionsof the master sheet which have been inked well interact with thesensitized paper to reproduce exactly, on the sensitized sheet, theinscription or image on the master.

In this fashion a direct positive can be prepared from the master sheetusing standard photographic emulsion as the sensitized sheet. Theprocess may also be used with Ozalid paper to produce a negative.

Because of the high ionizing power of alpha particles (approximately100,000 times that of the photons) and their short range, an extremelydense ionization takes place with each alpha particle. Thus the processmay be best accomplished with those materials generating alpha particlesupon bombardment with neutrons. Any type of sensitized paper may beemployed such as that having a photographic emulsion applied thereto orthe previously mentioned Ozalid paper.

While I have shown and described a preferred embodiment of my inventionand a preferred method of carrying out my improved process, the same isnot to be limited to all of the details shown but is capable ofmodification and variation within the spirit of the invention and withinthe scope of the appended claims.

What I claim is:

l. The method of reproducing printed, written or typed material whichcomprises placing such material on a master sheet in ink containing asubstance which is susceptible of radioactivity and which may laterreact with neutrons to produce high-energy alpha or beta particles,subjecting one side of said master sheet to the action of neutronradiation to only momentarily produce such particles while producing animage of the material on a sensitized sheet placed on the other side ofsaid master sheet.

2. The method of reproducing printed, written or typed material whichcomprises placing such material on a master sheet in ink containing asubstance which is susceptible of radioactivity and which may laterreact with neutrons to produce high-energy alpha or beta particles,placing said master sheet between a source of neutrons and a sheetof-material sensitive to high-energy alpha or beta particles, andsubjecting the material to neutron radiation from said source only whilesaid sheets are superposed.

3. The method of reproducing printed, written or typed material whichcomprises placing such material on a master sheet in ink containing asubstance which is susceptible of radioactivity and which may laterreact with neutrons to produce high-energy alpha or beta particles,superposing a sheet of sensitized material on said master sheet, passingsaid sheets between two cooperating closely spaced rolls to hold themflatly together and impinging, on said master sheet, neutrons from asuitable source to obtain on the sensitized sheet an image of thematerial on said master sheet.

4. The method of reproducing printed, written or typed material as inclaim 1 wherein the ink-contained substance is boron.

5. The method of reproducing written, printed or typed material as inclaim 1 wherein the ink-contained substance is lithium.

6. The method of reproducing printed, written or typed material whichcomprises placing such material on a master sheet in ink containing'boron, superposing a sensitized sheet on said master sheet and passingsaid master sheet and sensitized sheet over a source of neutrons toobtain on said sensitized sheet an image of the material on said mastersheet while shielding said neutron source except at a position adjacenta small portion of the area of said master sheet.

7. A device for the reproduction of written, printed or typed characterson sheet material which comprises a casing, a pair of closely spacedrolls rotatably mounted therein, means for rotating said rolls anddirecting sheet material therebetween, and a rod-like neutron sourceprovided at the axis of one of said rolls and extending axially of saidone roll.

8. A device for the reproduction of written, printed or typed characterson sheet material which comprises a casing, a pair of closely spacedrolls rotatably mounted therein, means for rotating said rolls anddirecting sheet material therebetween, a rod-like neutron sourceprovided at the axis of one of said rolls and extending axially of saidone roll, and said one roll having a hard outer 6 casing.

9. A device for the reproduction of written, printed or typed characterson sheet material which comprises a casing, a pair of closely spacedrolls rotatably mounted therein, means for rotating said rolls anddirecting sheet material therebetween, a rod-like neutron sourceprovided at the axis of one of said rolls and extending axially of saidone roll, and shielding means surrounding said one roll except in theneighborhood of its close approach to the other roll.

10. A device for the reproduction of written, printed or typedcharacters on sheet material which comprises a casing, a pair of closelyspaced rolls rotatably mounted therein, means for rotating said rollsand directing sheet material therebetween, a rod-like member comprisinga neutron source provided at the axis of one of said rolls and extendingaxially thereof and being substantially coextensive in length with saidone roll.

11. A device for the reproduction of written, printed or typedcharacters on sheet material which comprises a casing, a pair of closelyspaced rolls rotatably mounted therein, means for rotating said rolls atsubstantially equal peripheral speeds, an entrance chute for directingsheet material to the bite between said rolls, a discharge chute fordirecting sheet material away from said rolls, and a neutron sourcecomprising a metallic substance of rod-- like form extending axially ofone of said rolls and substantially coextensive in length with said oneroll.

12. A device for the reproduction of written, printed or typedcharacters on sheet material which comprises a casing, a pair of closelyspaced rolls rotatably mounted therein, means for rotating said rolls atsubstantially equal peripheral speeds, an entrance chute for directingsheet material to the bite between said rolls, a discharge chute fordirecting sheet material away from said rolls, a neutron sourcecomprising a metallic substance of rod-like form extending axially ofone of said rolls and substantially coextensive in length with said oneroll, and neutron-shielding means embracing said one roll except in theneighborhood of its close approach to the other roll.

13. The method of reproducing printed, written or typed material whichcomprises placing such material on a master sheet in ink containing asubstance susceptible of radioactivity, superposing a sheet ofphotosensitive material on said master sheet, and rendering said mastersheet radioactive substantially only while in contact with thephotosensitive sheet by bombarding the master sheet with neutrons from aneutron source.

14. The method of reproducing printed, written or typed material whichcomprises placing such material on a master sheet'in ink containing asubstance susceptible of radioactivity, superposing a sheet ofphotosensitive material on said master sheet, and bombarding the mastersheet with neutrons from a neutron source only while the master sheet isin contact with the sensitized sheet.

References Cited in the file of this patent UNITED STATES PATENTS2,230,618 Kallrnann Feb. 4, 1941 2,407,381 Pecher Sept. 10, 19462,603,755 De Ment July 15, 1952 OTHER REFERENCES Segre: AbstractApplication, published November 29, 1949, 628 0. 1529,

7. A DEVICE FOR THE REPRODUCTION OF WRITTEN, PRINTED OR TYPED CHARACTERSON SHEET MATERIAL WHICH COMPRISES A CASING, A PAIR OF CLOSELY SPACEDROLLS ROTATABLY MOUNTED THEREIN, MEANS FOR ROTATING SAID ROLLS ANDDIRECTING SHEET